Winders and rewinders are machines that roll lengths of paper, commonly known as paper webs into rolls. These machines are capable of rolling lengths of web into rolls at high speeds through an automated process. A winder is typically known as an apparatus that performs the very first wind of the web, forming what is generally known as a parent roll. A rewinder, on the other hand, is typically known as an apparatus that winds the web from the parent roll onto a log that is essentially a finished product. For instance, the paper web is unwound from a parent roll in a continuous fashion, and the rewinder winds the paper web onto cores supported on mandrels to provide individual, relatively small diameter logs. The rolled product log is then cut to designated lengths into the final product. Final products typically created by these machines and processes are toilet tissue rolls, paper towel rolls, paper rolls, and the like.
Various different types of winders exist. For instance, turret winders comprise a rotating turret assembly which support a plurality of mandrels for rotation about a turret axis. The mandrels travel in a circular path at a fixed distance from the turret axis. Hollow cores are loaded onto the winding mandrels upon which paper can be wound. The winding technique used in turret winders/rewinders is known as center winding. A center winding apparatus, for instance, is disclosed in U.S. Pat. Reissue No. 28,353 to Nystrand, which is incorporated herein by reference. In center winding, a mandrel is rotated in order to wind a web into a log, either with or without a core. Typically, the core is loaded and supported on a mandrel that rotates at high speeds at the beginning of a winding cycle and then slows down as the size of the rolled product being wound increases, in order to maintain a constant surface speed, approximately matching web speed. Also, typically, center winders can be preferable for efficiently producing soft-wound, higher bulk rolled products.
A second type of winding is known in the art as surface winding. A machine that uses the technique of surface winding is disclosed in U.S. Pat. No. 4,583,698 which is incorporated herein by reference. Typically, in surface winding, the web is wound onto the core via contact and friction developed with rotating rollers. A nip is typically formed between two or more co-acting roller systems. In surface winding, the core and the web that is wound around the core are usually driven by rotating rollers that operate at approximately the same speed as the web speed. Surface winding is preferable for efficiently producing hard-wound, lower bulk rolled products.
Another type of winder, known as a flex winder, can perform both center winding and surface winding or a combination of center winding and surface winding. Such an exemplary winding apparatus is disclosed in U.S. Patent Application Publication No. 2008/0105776, which is incorporated herein by reference. The winder includes a web transport apparatus that is used for conveying the web. Also included can be a plurality of independent winding modules. The winding modules can be independently positioned to independently engage the web as the web is conveyed by the web transport apparatus. The winding modules may be configured to wind the web to form a rolled product by center winding, surface winding, and combinations of center and surface winding. The winding modules are structurally and operationally independent of one another where if one module is disabled, another may still operate to produce the rolled product without shutting down the winder.
Registration and inspection systems can be used in connection with winders for a variety of purposes, including quality control purposes, process control purposes, material control purposes, and other suitable purposes. For instance, it can desirable to monitor and detect breaks in the webs, defects in the winding process (such as roll build defects, web transfer defects to the mandrel at the start of log wind, etc.), and to detect other parameters. It can also be desirable to gather data concerning web transfer and roll build during the winding process and determine the presence of defects warranting cull events. As used herein, a cull event is intended to refer to an event in which a rolled product is culled from a group of saleable products due to a defect in the rolled product.
Various methods of break detection and web inspection systems exist for monitoring web transfer, roll build, and other parameters of a winding process. Such inspection systems may use one or more photo-eyes or other sensors for basic web break detection and to trigger faults on winders. For instance, winders can have a photo-eye or sensor on both ends of the web at several locations in the machine direction that indicate on which side of the web transport apparatus a break in the web occurs. A photo-eye that shoots across the cross direction of logs on a turret style winder can also be used to detect winding disruptions.
Existing break detection and inspection systems, however, lack robustness in terms of sensitivity, configurability and integration necessary for application to winders that provide for greater toleration and masking of winding defects. For instance, certain inspection systems require a web break or large winding defect to trigger a cull event. Applicability of such inspection systems to winders with increased defect toleration and masking, such as flex winders, can result in the culling of saleable products, leading to waste, or in the providing of products with rejectable defects to consumers. Moreover, existing inspection systems provide limited defect profiling and scan capabilities for associating winding defect types with defect locations during the winding process.
Thus, there is a need for a registration and inspection system that can be used in conjunction with winders that provide for increased toleration and masking of winding defects that overcomes the above-mentioned disadvantages.